1. Field of the Invention
The present invention relates to an organic light emitting display device.
2. Description of the Related Art
Electroluminescence display devices, which are flat panel display devices, are self-emissive display devices with a wide viewing angle, good contrast, and fast response time. Organic light emitting display devices including a light emission layer formed of an organic material have improved brightness, driving voltage, response time characteristics and multi-colorization characteristics, as compared to inorganic light emitting display devices.
Recently, research for applying a touch panel function to organic electroluminescent display devices has been conducted. The research is directed to improve user convenience by installing a touch panel function in a display, wherein the touch panel function is performed by inputting commands on a screen of the display with a user's finger or a pen type instrument.
A touch panel can be a resistive film type touch panel or a capacitive type touch panel, according to its operational principle. In the resistive film type touch panel, when a voltage is applied between two opposing conductive layers, a user presses a screen to make the two conductive layers come into contact with each other. A voltage or current variation generated at the contact point is then detected to read a coordinate value of the contact point.
In the capacitive type touch panel, while capacitance charging or discharging iteratively keeps taking place on a transparent conductive film or a transparent conductive glass, a small quantity of electric charges is accumulated between the conductive film and a stylus used as a pen type input instrument. The electric charge quantity is detected from four input points which are converted into a coordinate value.
To install a touch panel function in organic light emitting display devices, a touch panel is disposed on an organic light emitting display panel, thereby increasing the thickness of the organic light emitting display device. Also, the organic light emitting display device generally includes a polarizing plate in order to prevent or reduce reflection of external light, and thus the organic light emitting display device becomes thicker due to the polarizing plate and the touch panel included therein.